Connector for a power supply

ABSTRACT

A power supply connector includes a cable receptacle, a front bulkhead insulator and a rear bulkhead insulator. The bulkhead insulators are mounted on the cable receptacle and the power supply chassis. At least one O ring is disposed between the front and rear bulkhead insulators, to seal out water. The front bulkhead insulator includes a stepped portion that mates with a stepped portion on the rear bulkhead insulator. The front bulkhead insulator provides an elongated path from the chassis to the cable receptacle. Also, an O ring is disposed between the cable receptacle and the front bulkhead insulator, to seal out water.

This is a continuation of application Ser. No. 08/780,992 filed on Jan.9, 1997, now U.S. Pat. No. 5,902,150.

FIELD OF THE INVENTION

This invention relates generally to a connector for a power supply suchas a welding power supply and, in particular, to a connector thatreduces the likelihood of shorting out or breaking over or arcing fromthe internal or external electrical connection (which may beelectrically hot) to the power supply chassis.

BACKGROUND OF THE INVENTION

Power supplies such as welding power supplies are used to provide highamperage current. Typically, in a welding power supply, a pair of outputterminals is provided. A welding cable connected to the welding torch(or stinger, drive assembly or welding circuit) is inserted into one ofthe two output terminals. The other output terminal receives a weldingcable which is connected to the workpiece being welded. Typically, theconnectors are twist lock type connectors (also called internationalconnectors), the power supply has a female connector, and the weldingcable has a mating male connector. In some designs the cable has afemale connector and the power supply a male connector.

One prior art twist lock connector is shown in FIGS. 1-3. The prior artconnector, as shown in FIG. 3, includes a twist lock receptacle 101, afront bulkhead insulator 102, a rear bulkhead insulator 103, a lockwasher 104, a nut 105, a washer 106, a lock washer 107 and a hex bolt108. Hex bolt 108 and washers 104, 106 and 107 are comprised of zincplated steel, and twist lock connector 101 and nut 105 are comprised ofbrass. The front and rear bulkhead insulators, 102 and 103 are phenolic.The steel and brass components are used to provide for adequateelectrical contact. A phenolic is typically used because it is a goodinsulator, flame-retardant, and will not melt.

Referring now to FIG. 1, a view of the prior art connector from outsidethe power supply is provided. Front bulkhead insulator 102 includes aridge, as depicted by the concentric circles of FIG. 1. The innerperimeter of front bulkhead insulator 102 is hexagonal in shape. A twistlock receptacle 101 has a hexagonal outer perimeter and fits tightlywithin front bulkhead insulator 102. Twist lock receptacle 101 includesa circular opening 116 having an axial notch 115. A circumferential,slightly helical, notch 117, within twist lock receptacle 101, may beseen in FIGS. 2 and 3. When the welding cable is connected, a key on themale connector attached to the welding cable mates with notch 115, andwhen the cable connector has been inserted all of the way, the cableconnector is rotated and the key turns in circumferential notch 117. Themale connector is pulled tightly to the face of the female connector bythe action of the helical-shaped notch. Thus, the cable connector islocked into place and the desired electrical contact is obtained.

Referring now to FIG. 2, front bulkhead insulator 102 is inserted into ahole in a power supply chassis 112. The hole in power supply chassis 112includes a notch which receives a key 119 on front bulkhead insulator102. Thus, front bulkhead insulator 102 does not twist when the maleconnector on the welding cable is being rotated to lock it into place.

An end 120 of twist lock receptacle 101 extends within the welding powersupply and rear bulkhead insulator 103 is mounted thereon. Rear bulkheadinsulator 103 and front bulkhead insulator 102 are designed to mate andwelding power supply chassis 112 is sandwiched between them. Also, thenotch on front bulkhead insulator 102 is received in a similarly andoppositely notched portion 122 of rear bulkhead insulator 103, toprevent the inner portion of the connector from rotating.

Inner end 120 of twist lock receptacle 101 is threaded and nut 105 hasmating threads to allow nut 105 to be threadedly mounted on twist lockreceptacle 101. Thus, nut 105 and lock washer 104 are used to maintaincontact between front bulkhead insulator 102, welding power supplychassis 112 and rear bulkhead insulator 103.

End 120 of twist lock receptacle 101 is hollow, and its inner surface isthreaded. The threaded interior portion receives hex bolt 108, aboutwhich washer 106 and lock washer 107 are disposed. As shown in FIG. 2,an internal electrical connection 110 is placed between the inner end oftwist lock receptacle 101 and washer 106. The internal electricalconnection 110 may be a copper lug, an aluminum bus bar, or any otherinternal electrical connection. Some prior art connectors include a gasfitting that replaces hex bolt 108, and an O ring disposed within twistlock receptacle 101 near notch 117 that seals the gas flow path (throughthe connector and into the cable).

Thus, it may be seen that the prior art connectors provided for a secureand locking electrical connection between an internal electricalconnection and the welding cable.

It is not unusual for welding power supplies to be used outside, forexample at construction sites. Thus, they are often exposed to rain ormay otherwise get wet. Also, to obtain IEC certification.(or othercertifications such as UL, CSA, NEMA etc.), welding power supplies mustbe subjected to a “rain test”. In such a test, the power supply will besubjected to water, to ensure that premature failures in the field willnot occur.

However, in the prior art connectors water sometimes seeps between frontbulkhead insulator 102 and welding chassis 112. The water then seepsdown between front bulkhead insulator 102 and rear bulkhead insulator103. The potential water leakage path is labelled 118, and is shown as asolid black line. As water leaks in along path 118, it may provide aconductive path from twist lock receptacle 101, which is electricallyhot, to chassis 112, which should be grounded. Thus, this path mayprovide an undesirable short.

It is typical to provide a welding power supply with a high frequencyarc starter. A high frequency arc starter provides a low current, buthigh voltage, high frequency signal. Such a high voltage signal can arcalong path 118 from twist lock receptacle 101 to welding power supplychassis 112. This problem is exacerbated when water seeps into path 118.

One prior art attempt to solve the problems of water leakage and highfrequency arcing is to apply a RTV (room temperature vulcanizing)compound in an attempt to seal path 118. However, such a compound isdifficult to apply and does not adequately solve the problem.Additionally, a second potential water seepage path 118A may be foundbetween twist lock receptacle 101 and front bulkhead insulator 102.

Accordingly, it is desirable to provide a power supply connector thatwill reduce the likelihood of water leaking into the power supply andcausing a short therein, or to have a short during high frequency arcstarting. Such a connector should preferably be a locking cablereceptacle, with an anti-rotational fitting and relatively simple andeasy to manufacture.

SUMMARY OF THE PRESENT INVENTION

One aspect of the invention is a power supply connector that includes acable receptacle. A front bulkhead insulator and a rear bulkheadinsulator are mounted on the cable receptacle. At least one O ring isdisposed between the front and rear bulkhead insulators, to seal outwater. In alternative embodiments the front bulkhead insulator includesa stepped portion that mates with a stepped portion on the rear bulkheadinsulator. The front bulkhead insulator may provide for an elongatedpath from the chassis to the cable receptacle. Also, an O ring may bedisposed between the cable receptacle and the front bulkhead insulator,to seal out water. The connector may be a twist lock connector, and thechassis may be placed between the bulkhead insulators.

Another aspect of the invention is a power supply connector including acable receptacle. A front bulkhead insulator mounts on the cablereceptacle, and on the welding power supply chassis. A rear bulkheadinsulator is also mounted on the cable receptacle and the welding powersupply chassis. The front bulkhead insulator includes a stepped portionand the rear bulkhead insulator includes a stepped portion and thebulkhead insulators mate with one another. In alternative embodiments ofthis aspect of the invention the front bulkhead insulator provides foran elongated path from the chassis to the cable receptacle.Alternatively, an o ring may be disposed between the cable receptacleand the front bulkhead insulator. The connector may be a twist lockconnector, and the chassis may be placed between the bulkheadinsulators.

A third aspect of the invention is a power supply connector that alsoincludes a cable receptacle and a front bulkhead insulator mounted aboutthe cable receptacle and on a welding power supply chassis. A rearbulkhead insulator is also mounted about the cable receptacle and on thewelding power supply chassis. The front bulkhead insulator is shaped toprovide an elongated path from the chassis to the cable receptacle.Alternatives to this embodiment include an O ring disposed between thecable receptacle and the front bulkhead insulator. Also, the cablereceptacle may be a twist lock receptacle, and the chassis may besandwiched between the bulkhead insulators.

A fourth aspect of the invention is a power supply connector that alsoincludes a cable receptacle and a front bulkhead insulator mounted aboutthe cable receptacle and on a welding power supply chassis. A rearbulkhead insulator is also mounted about the cable receptacle and on thewelding power supply chassis. An O ring disposed between the cablereceptacle and the front bulkhead insulator. In an alternativeembodiment the cable receptacle may be a twist lock receptacle, and thechassis may be sandwiched between the bulkhead insulators.

Other principal features and advantages of the invention will becomeapparent to those skilled in the art upon review of the followingdrawings, the detailed description and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view of a connector of a prior art connector;

FIG. 2 is a cross-section taken along Line A—A of FIG. 1;

FIG. 3 is an expanded view of a cross-section taken along Line A—A ofFIG. 1;

FIG. 4 is a front view of a connector constructed in accordance with thepresent invention;

FIG. 5 is a cross-sectional view of the connector of FIG. 4, taken alongLine A—A;

FIG. 6 is an expanded view of the connector of FIG. 4, taken along LineA—A;

FIG. 7 is a front view of a connector suitable for receiving a gasfitting, constructed in accordance with the present invention;

FIG. 8 is a cross-section of the connector of FIG. 7, taken along LineA—A; and

FIG. 9 is an expanded cross-section of the connector of FIG. 7, takenalong Line A—A.

Before explaining at least one embodiment of the invention in detail itis to be understood that the invention is not limited in its applicationto the details of construction and the arrangement of the components setforth in the following description or illustrated in the drawings. Theinvention is capable of other embodiments or of being practiced orcarried out in various ways. Also, it is to be understood that thephraseology and terminology employed herein is for the purpose ofdescription and should not be regarded as limiting. Like referencenumerals are used to indicate like components.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

While the present invention will be illustrated with reference to twoparticular welding power supply connectors, it should be understood atthe outset that the invention can also be employed for other powersupply connectors, including connectors comprised of a differentmaterial, or connectors of other designs, or male connectors.

One embodiment of the invention is shown in FIGS. 4-6. An expandedcross-sectional view of an inventive connector is shown in FIG. 6 toinclude an O ring 213, a twist lock receptacle 201, an O ring 214, afront bulkhead insulator 202, an O ring 215, a rear bulkhead insulator203, lock washer 104, nut 105, washer 106, lock washer 107, and hex bolt108. In the preferred embodiment, twist lock receptacle 201 and nut 105are comprised of brass. Lock washer 104, washer 106, lock washer 107 andhex bolt 108 are comprised of steel, and preferably zinc-plated. Thesematerials are brass and/or steel with zinc-plating to provide foradequate electrical connection between the internal electricalconnection (110 of FIG. 5) and the welding cable (brass) and to providemechanical stability (steel). Front bulkhead insulator 202 and rearbulkhead insulator 203 are preferably comprised of a phenolic because itis a good insulator, it does not-melt easily, and it is flame-retardant.O rings 213, 214, and 215 are preferably comprised of silicone rubberwhich adequately seals the parts between which they are disposed.

Referring now to FIG. 4, a front view of the inventive connector isshown. It may be seen that from the front, the connector looks much likethe prior art connector of FIGS. 1-3. For example, the connector isdesigned to receive the same male welding cable connector the prior artreceived, and thus includes circumferential, slightly helical, and axialnotches (FIG. 5) just like the prior art's.

Referring further to FIG. 5, an assembled connector is shown mountedabout chassis 112 and attached to internal electrical connection 110. Aswith the prior art design, twist lock receptacle 201 is disposed withinfront bulkhead insulator 202. However, an O ring 214 is placed around acircumferential notch 212 (FIG. 6) on twist lock receptacle 201. O ring214 thus seals the potential water leakage path between twist lockreceptacle 201 and front bulkhead insulator 202. This also provides abarrier to keep an HF signal from shorting to the chassis.

Also, a circumferential notch 218 is provided to receive a gas O ring213. Gas O ring 213 is provided so that when a gas connection (oftenused in various welding processes), is used, the gas will be adequatelysealed and will not leak outside the welding cable.

Front bulkhead insulator 202 is provided with a stepped portion 220which is received by a similarly stepped portion of rear bulkheadinsulator 203. Stepped portion, as used herein, means that the surfacehas at least three segments, wherein the segments are separated by achange in direction (i.e., an angle or a bend in the surface). In thepreferred embodiment the segments are defined by ninety degree angles,although other angles may be used.

O Ring 215 is seated on a notch 221 of front bulkhead insulator 202.When assembled, as shown in FIG. 5, rear bulkhead insulator 203 mountson twist lock receptacle 201 and front bulkhead insulator 202. Weldingpower supply chassis 112 is disposed there-between, and has a notch (asdid the prior art) to prevent rotation of the connector when the weldingcable is connected thereto. Lock washer 104, nut 105, washer 106, lockwasher 107 and hex bolt 108 are used in the same manner as they wereused in the prior art.

It may be seen that water leakage path 118 of the prior art is sealed byO ring 215 in this inventive design. Also, stepped portion 220 lengthensthe path from chassis 112 to twist lock receptacle 201. Thus, for an arcto occur it must traverse an elongated path and a seal. As used herein,elongated path means a path having a greater distance than a straightline (or close to the same as distance as a straight line). In thepreferred embodiment the elongated path is obtained using a steppedportion. However, in an alternative the stepped portion is omitted, andthe elongated path is obtained by increasing the length of frontbulkhead insulator 202. Both the seal and the elongated path helpgreatly reduce the likelihood of arcing during HF arc starting or evenafter the power supply has been subjected to an IEC “rain test.” Also, Oring 214 prevents water from leaking in between twist lock receptacle201 and front bulkhead insulator 202.

FIGS. 7-9 show a second embodiment of the inventive welding power supplyconnector. As may be seen in FIGS. 8 and 9, the connector issubstantially identical to the connector of FIGS. 4-6, but hex bolt 108is replaced with a gas fitting 301. Gas fitting 301 is used to providegas from an internal gas supply through the inner portion of twist lockreceptacle 201 to the welding cable.

Numerous modifications may be made to the present invention which stillfall within the intended scope hereof. Thus, it should be apparent thatthere has been provided in accordance with the present invention anapparatus for connecting a cable to a power supply that fully satisfiesthe objectives and advantages set forth above. Although the inventionhas been described in conjunction with specific embodiments thereof, itis evident that many alternatives, modifications and variations will beapparent to those skilled in the art. Accordingly, it is intended toembrace all such alternatives, modifications and variations that fallwithin the spirit and broad scope of the appended claims.

What is claimed is:
 1. A power supply connector comprising: a cablereceptacle, which forms part of a current carrying path through theconnector; a bulkhead insulator mounted about the cable receptacle andon a welding power supply chassis, which is not part of the currentcarrying path; and an O ring disposed between the cable receptacle andthe bulkhead insulator.
 2. The connector of claim 1 wherein the cablereceptacle is a twist lock receptacle.
 3. The connector of claim 1wherein the bulkhead insulator includes a stepped portion.
 4. Theconnector of claim 3 wherein the bulkhead insulator provides for anelongated path from the chassis to the cable receptacle.
 5. Theconnector of claim 1 wherein the bulkhead insulator provides for anelongated path from the chassis to the cable receptacle.